---
id: "CVE-2026-71553"
kind: "vulnerability"
aliases: ["CVE-2026-71553", "GHSA-vmg4-6gfg-83qx"]
title: "ApostropheCMS: 2nd-order prototype pollution via PATCH leading to single-request persistent DoS"
severity: "high"
cvss: 7.1
epss: 0.00429
exploited: false
status: "open"
category: "package"
products: [{"name": "apostrophe", "fixed": ["4.32.1"], "affected": "<= 4.32.0", "ecosystem": "npm"}]
ecosystems: ["npm"]
tags: ["apostrophe", "cwe-1321", "node.js", "package", "self-hosted"]
not_affected_if: ["auth-required", "fixed-version"]
published_at: "2026-08-17T20:16:46+00:00"
first_seen_at: "2026-10-28T15:14:20+00:00"
updated_at: "2026-10-28T15:33:37+00:00"
sources: [{"source": "ghsa", "url": "https://github.com/advisories/GHSA-vmg4-6gfg-83qx", "first_seen_at": "2026-10-28T15:14:20+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-71553", "first_seen_at": "2026-10-28T15:33:37+00:00"}]
---

# ApostropheCMS: 2nd-order prototype pollution via PATCH leading to single-request persistent DoS

A crafted PATCH request to an ApostropheCMS article endpoint overwrites the global toString function through prototype pollution, so a single request can persistently break the application. The sources describe this as denial of service, not code execution.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- npm:apostrophe affected <= 4.32.0 fixed 4.32.1

## How to check

- Check the installed version with `npm ls apostrophe` and see whether it is `4.32.0` or lower.
- Review whether editor accounts can send PATCH requests to `/api/v1/article/<id>` from untrusted input.

## Fix

- Upgrade `apostrophe` to `4.32.1`.

## Timeline

- 2026-10-28T15:14:20+00:00 ghsa https://github.com/advisories/GHSA-vmg4-6gfg-83qx
- 2026-10-28T15:33:37+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-71553

## From the sources

ApostropheCMS is an open-source Node.js content management system. In 4.32.0 and earlier, PATCH /api/v1/article/:id accepts the inherited path toString.call and passes it through the utility module to apos.util.set() and apos.util.get(), allowing an authenticated editor to overwrite the shared Object.prototype.toString function's call property and cause a persistent process-wide denial of service until restart.

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